KR100318386B1 - Mask assembly for cathode ray tube - Google Patents

Abstract

The present invention relates to a mask assembly for cathode ray tube, which can suppress the shadowing of a shadow mask to prevent deterioration of image quality and to reinforce the strength of the shadow mask. And a plurality of spring members for fixing the mask frame to the panel, wherein each of the long side portion and the short side portion of the shadow mask and the mask frame has a convex curved surface having a predetermined radius of curvature toward the outside of the mask assembly. According to such a configuration, the shadow mask has an advantageous property to improve the strength by increasing the area of the non-perforated area, and can reduce the amount of domming by reducing the amount of heat per unit area. In addition, the mask frame may prevent local shadowing of the shadow mask by inducing natural shadowing of the shadow mask due to the curved shape of each edge portion.

Description

Mask assembly for cathode ray tube

The present invention relates to a mask assembly for a cathode ray tube, and more particularly to a mask assembly for cathode ray tubes that can suppress the shadowing of the shadow mask to prevent image degradation and at the same time reinforce the strength of the shadow mask.

In general, the mask assembly is disposed to be parallel to the panel forming a fluorescent screen on the inner side to separate and landing three stem electron beams emitted from the electron gun with the corresponding phosphor. For this purpose, the mask assembly includes a plurality of beam passing holes. And a shadow mask for forming and separating and landing the electron beam, a mask frame for supporting the shadow mask, and a plurality of spring members for fixing the mask frame to the panel.

Here, since the shadow mask is made of an extremely thin metal material, when the thermal energy increases due to the electron beam collision, the shadow mask causes a domming phenomenon that convexly expands toward the panel. It acts as a major cause of deterioration of image quality, such as impeding accurate landing of the electron beam and lowering color purity.

This deterioration in image quality represents a serious problem, especially when a portion of the shadow mask is locally dominated, and this local doming is particularly one-third or two-third horizontally in the center of the shadow mask. For example, in the case of 28-inch cathode ray tube, the local domming amount is approximately 70 μm.

Local shadowing of the shadow mask occurs for various reasons, but one of the causes is the shape of the shadow mask. FIG. 7 is a perspective view of a shadow mask according to the prior art, and as shown, the shadow mask 1 includes a mask portion 3 forming a plurality of beam passing holes 1a and four edges of the mask portion 3. The long side and short side of the shadow mask 1 are substantially straight with a curvature radius of approximately 20,000 mm.

As described above, the rectangular shadow mask 1 having the long side portions and the short side portions substantially linearly has a tendency to cause local doming because the doming of the mask portion 3 is not easy to occur uniformly as a whole due to the characteristics of the rectangle. have. Therefore, the screen portion corresponding to some point in the locally-doped shadow mask 1 exhibits a severe deterioration in image quality, and thus shows a problem of degrading the display quality of the cathode ray tube.

Therefore, the present invention has been devised to solve the above problems, and an object of the present invention is to prevent shadowing, in particular, of local shadowing, thereby preventing deterioration of image quality due to local shadowing, and It is an object of the present invention to provide a mask assembly for a cathode ray tube that can enhance strength.

1 is a partial cutaway perspective view of a cathode ray tube including a mask assembly according to the present invention;

Figure 2 is an exploded perspective view of the mask assembly according to the present invention.

3 is a plan view of the mask assembly according to the present invention.

4 and 5 are schematic plan views of the mask assembly according to the invention.

6 is an enlarged view of a portion A of FIG. 3;

7 is a perspective view of a shadow mask according to the prior art.

In order to achieve the above object, the present invention,

A shadow mask for forming a plurality of beam passing holes to separate and landing the electron beam with the corresponding phosphor, a mask frame welded to the periphery of the shadow mask to support the shadow mask, and a stud pin embedded in the mask frame and the panel In the mask assembly for a cathode ray tube comprising a plurality of spring members which are interposed in to fix the mask frame to the panel, the long side and the short side of the shadow mask and the mask frame is set within the range according to Equations 1 to 4 below. It provides a mask assembly for a cathode ray tube to be made.

4500 ≤ R1 ≤ 5500

1500 ≤ R2 ≤ 2500

4500 R1 '<5500

1500 R2 '<2500

Here, R1 and R2 represent curvature radii (mm) of the long and short sides of the shadow mask, respectively, and R1 'and R2' represent curvature radii (mm) of the long and short sides of the mask frame, respectively.

As such, the long and short sides of the shadow mask and the mask frame are formed into rounds having a predetermined radius of curvature, so that the shadow mask has a characteristic of increasing strength by increasing the area of the non-perforated area and reducing the amount of heat per unit area. The amount of doming may be further reduced. In addition, each of the long side portion and the short side portion of the curved surface induces natural doming, thereby preventing local doming, and thus having a merit of preventing partial degradation of image quality.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a partial cutaway perspective view of a cathode ray tube including a mask assembly according to the present invention.

As shown in the drawing, the cathode ray tube includes a panel 4 for forming a fluorescent film screen 2 on its inner surface, a neck portion 8 for mounting an electron gun 6 on its inner circumferential surface, and the panel 4 and a neck portion 8. The funnel 10 of the shape of a trumpet which connects) is combined to form a tube 12.

The fluorescent film screen 2 is a film in which a plurality of green, blue, and red phosphors are patterned in a predetermined shape, and the phosphors are excited by scanning the electron beam 14 emitted from the electron gun 6 to produce a predetermined image. Will be implemented.

In this case, the shadow mask 20 disposed on the rear surface of the fluorescent film screen 2 is manufactured with a curvature similar to that of the screen portion 4a of the panel 4 and includes a plurality of beam passing holes 20a corresponding to the phosphor pattern. ) To separate and land the three stem electron beams 14 emitted from the electron gun 6 into the respective phosphors.

As such, the shadow mask 20, which plays an important role in implementing the color image, is made of an extremely thin metal material, and thus causes a domming phenomenon that convexly expands toward the screen portion 4a of the panel 4. It is important to suppress the ming phenomenon. Accordingly, the mask assembly according to the present embodiment effectively prevents the shadowing of the shadow mask 20, in particular the localized one.

2 is an exploded perspective view of the mask assembly according to the present invention, Figure 3 is a plan view of the mask assembly.

As shown in the drawing, the mask assembly includes a shadow mask 20, which is a color screening means, a mask frame 30 supporting the shadow mask 20, and a plurality of masks fixing the mask frame 30 to the panel 4. It consists of a corner pin spring (40).

In more detail, the shadow mask 20 includes a mask portion 26 forming a plurality of beam passing holes 20a and a skirt portion 28 formed by bending four edges of the mask portion 26. And the mask part 26 includes a hole part 22 in which a plurality of beam passing holes 20a are formed, and a hole part 24 positioned between the hole part 22 and the skirt part 28. )

The mask frame 30 is bent toward the shadow mask 20 from four edges of the rectangular bottom portion 32 forming the opening 32a for electron beam passing through, and the shadow mask 20 is formed as a shadow mask. And a side portion 34 welded to the skirt portion 28 of the 20.

The shadow mask 20 having such a configuration is fitted into or out of the mask frame 30, and then around the skirt portion 28 of the shadow mask 20 and the side portions 34 of the mask frame 30 that are in contact with each other. It is integrated by performing a series of welding operations along the.

The mask frame 30 integrated with the shadow mask 20 is fixed to a stud pin (not shown) embedded in the inner surface of the panel 4 by the corner pin spring 40 and mounted on the tube 12.

Here, the shadow mask 20 and the mask frame 30 according to the present embodiment are formed by rounding each of the long side portion and the short side portion with a predetermined curvature, as shown in FIG. 3. Each of the long side portion and the short side portion of the mask frame 30 is formed to be convexly rounded with a predetermined curvature toward the outside of the mask assembly.

Curvature formation of the long side portion and the short side portion is to induce a natural doming of the shadow mask 20 to prevent local doming. The mask assembly according to the present embodiment has a long side portion and a short side of the shadow mask 20. The unit is set so as to be set within the range according to the following expressions (1) and (2).

[Equation 1]

4500 ≤ R1 ≤ 5500

[Equation 2]

1500 ≤ R2 ≤ 2500

Here, R1 (mm) represents the radius of curvature of the long side of the shadow mask 20, and R2 (mm) represents the radius of curvature of the short side of the shadow mask 20.

As shown in FIG. 4, the long-side curvature radius R1 of the shadow mask 20 represents a distance from the C1 point, which is the curvature center of the long-side portion of the shadow mask 20, to a point on the long-side portion, and the short-side curvature. The radius R2 represents the distance from the point C2 that is the center of curvature of the short side of the shadow mask 20 to one point on the short side.

In addition, the mask assembly according to the present exemplary embodiment is configured such that the long side portion and the short side portion of the mask frame 30 are set within the ranges according to Equations 3 and 4 below.

[Equation 3]

4500 <R1 '<5500

[Equation 4]

1500 <R2 '<2500

Here, R1 '(mm) represents the radius of curvature of the long side of the mask frame 30, and R2' (mm) represents the radius of curvature of the short side of the mask frame 30.

As shown in FIG. 5, the long side portion and the short side radius of curvature R1 'and R2' of the mask frame 30 are each C1 'from the center of curvature of the long side of the mask frame 30 to one point on the long side portion. And the distance from the point C2 'which is the center of curvature of the short side of the mask frame 30 to one point on the short side.

The radius of curvature of the shadow mask 20 and the mask frame 30 set as described above may be adjusted within the ranges of the above-described Equations 1 to 4 in consideration of the size and the domming characteristic of the cathode ray tube. The preferred range is that the long side radius of curvature of the shadow mask 20 and the mask frame 30 is approximately 5,000 mm, and the short side radius of curvature of the shadow mask 20 and the mask frame 30 is approximately 2,000 mm.

As described above, the dominant suppression effect of the shadow mask 20 and the mask frame 30 formed in the round will be described.

FIG. 6 is an enlarged view of portion A of FIG. 3, as shown in FIG. 3, as the long side portion and the short side portion of the shadow mask 20 are convexly rounded toward the outside of the shadow mask 20. The area of the non-hole 24 positioned around the hole 22 may be further enlarged than before.

The shadow mask 20 may reinforce the mechanical strength of the mask portion 26 due to the enlargement of the area of the non-porous portion 24, and may increase the amount of heat per unit area of the mask portion 26 when the thermal energy is increased by the electron beam collision. Since it can reduce, the doming of the perforation part 22 can be suppressed effectively.

In addition, since the long side portion and the short side portion of the mask frame 30 are also formed in a round shape corresponding to the shape of the shadow mask 20, the curved shape may induce natural doming than the conventional straight shape, and thus the shadow mask 20 By uniformly inducing the masking portion 26 of the mask portion 26, it is possible to effectively suppress local doming, which is caused by a particular portion being further deformed.

As described above, the mask assembly according to the present embodiment has a domingo suppression property, and the result of measuring the local doming amount of the shadow mask 20 in comparison with a conventional mask assembly mounted on the same 32-inch cathode ray tube is as follows. Table 1 shows.

Local Domming Amount (μm) Example 40 Prior art 82

The local domming amount was measured at the point P, which is one-third from the center point of the shadow mask to one end side, as shown in FIG. 3, in the mask assembly according to the prior art and the present embodiment.

As shown in Table 1 above, the mask assembly according to the present embodiment can effectively suppress local doming of the shadow mask 20, thereby preventing deterioration in image quality of a specific part due to local doming. Inducing uniform doming generally has the advantage of reducing the overall amount of domming.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

As described above, the mask assembly according to the present invention forms the long side and the short side of each of the shadow mask and the mask frame into rounds having a predetermined radius of curvature, thereby expanding the non-perforated area of the shadow mask to compensate for the mechanical strength. Due to the reduction in the amount of heat per unit area, the amount of domming of the mask portion can be effectively reduced.

In addition, due to the shape characteristics of the mask frame, natural shadowing of the shadow mask is induced, thereby preventing localized shadowing, thereby preventing partial deterioration of image quality. Has the effect.

Claims (2)

A shadow mask for forming a plurality of beam passing holes to separate and landing the electron beam with the corresponding phosphor, a mask frame welded to the periphery of the shadow mask to support the shadow mask, and a stud pin embedded in the mask frame and the panel In the mask assembly for a cathode ray tube comprising a plurality of spring members interposed in the fixing the mask frame to the panel, Each long side portion and the short side portion of the shadow mask is to be set within the range according to the following equations (1) and (2) for the cathode ray tube mask assembly. [Equation 1] 4500 ≤ R1 ≤ 5500 [Equation 2] 1500 ≤ R2 ≤ 2500 here, R1 is the radius of curvature of the long side of the shadow mask (mm), R2 is the radius of curvature of the short side of the shadow mask (mm). The mask assembly for a cathode ray tube according to claim 1, wherein each of the long side portion and the short side portion of the mask frame is set within a range according to Equations 3 and 4 below. [Equation 3] 4500 <R1 '<5500 [Equation 4] 1500 <R2 '<2500 here, R1 'is the radius of curvature of the long side of the mask frame (mm), R2 'is the radius of curvature of the short side of the mask frame (mm).